The embodiments of the present invention relate to a power supply control device, a storage system, a control method of the power supply control device, a control method of a disk array unit and a computer readable medium thereof. More particularly, it relates to a method for controlling power supply of a disk array unit that can perform multi-platform connection with a plurality of host devices with different power supply control specifications.
In order to improve the response of write processing from a host device, the disk array unit notifies the host device of writing completion when the disk array unit completes writing data in cache memory. The disk array unit writes data held in the cache memory to a hard disk drive when the host device is not writing other data in the cache memory.
For this reason, the disk array unit has a battery, etc. in preparation for when electric power is not supplied to the disk array unit due to a power failure, etc. in a state where data exists in the cache memory. The disk array unit backs up the data held in the cache memory by using the battery.
Examples of the disk array unit technology are disclosed below.
Patent Document 1 discloses a disk array unit which has a cache saving area of a recording medium that is formed in an area that is different from a user data area of the recording medium. When a power failure occurs, the disk array unit copies contents of the cache memory into the cache saving area of the recording medium by using a back up power supply.
Patent Document 2 discloses that a management device manages an external storage device of the disk array unit by using simple network management protocol (SNMP). Patent Document 2 also discloses that when abnormalities occur in a main power supply of the external storage device, the disk array unit supplies electric power from an auxiliary power supply to a semiconductor memory, a hard disk, and a control unit.    [Patent Document 1] JP-A-2000-357059    [Patent document 2] JP-A-2003-150415
In Patent Document 1 and Patent Document 2, the uninterruptible power supply device supplies electric power when a power supply failure of the disk array unit occurs. However, software for controlling the uninterruptible power supply device is needed, and the specification for controlling the uninterruptible power supply differs according to the company that makes the uninterruptible power supply. For this reason, there is a problem that, when managing the plurality of host devices and the disk array units with different power supply control specifications collectively, management of the power supply is very complicated.
A purpose of certain embodiments of the present s is to provide a power supply control device which can easily control the power supply of a storage system that comprises a plurality of host devices and disk array units with different power supply control specifications and which does not lose the data held in the cache memory.